Exercise effects in Huntington disease

Abstract

Huntington disease (HD) is a relentlessly progressive neurodegenerative disorder with symptoms across a wide range of neurological domains, including cognitive and motor dysfunction. There is still no causative treatment for HD but environmental factors such as passive lifestyle may modulate disease onset and progression. In humans, multidisciplinary rehabilitation has a positive impact on cognitive functions. However, a specific role for exercise as a component of an environmental enrichment effect has been difficult to demonstrate. We aimed at investigating whether endurance training (ET) stabilizes the progression of motor and cognitive dysfunction and ameliorates cardiovascular function in HD patients. Twelve male HD patients (mean ± SD, 54.8 ± 7.1 years) and twelve male controls (49.1 ± 6.8 years) completed 26 weeks of endurance training. Before and after the training intervention, clinical assessments, exercise physiological tests, and a body composition measurement were conducted and a muscle biopsy was taken from M. vastus lateralis. To examine the natural course of the disease, HD patients were additionally assessed 6 months prior to ET. During the ET period, there was a motor deficit stabilization as indicated by the Unified Huntington’s Disease Rating Scale motor section score in HD patients (baseline: 18.6 ± 9.2, pre-training: 26.0 ± 13.7, post-training: 26.8 ± 16.4). Peak oxygen uptake ($\dot{V}{\text{O}}_{{ 2 {\text{peak}}}}$) significantly increased in HD patients (∆$\dot{V}{\text{O}}_{{ 2 {\text{peak}}}}$ = +0.33 ± 0.28 l) and controls (∆$\dot{V}{\text{O}}_{{ 2 {\text{peak}}}}$ = +0.29 ± 0.41 l). No adverse effects of the training intervention were reported. Our results confirm that HD patients are amenable to a specific exercise-induced therapeutic strategy indicated by an increased cardiovascular function and a stabilization of motor function.